Collaborative Research: Systematic Comparisons of Regular and Slow Earthquakes in Central and Southern California

合作研究：加州中部和南部定期地震和慢震的系统比较

• 批准号: 1736197
• 负责人: Zhigang Peng
• 金额: $ 16.1万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-01 至 2020-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1736197&HistoricalAwards=false
• 关键词: Collaborative; Research; Systematic; Comparisons; Regular

Nontechnical This project aims to understand different behaviors of regular and slow earthquakes in Central and Southern California. The recent discovery of slow earthquakes broadens our view on how active faults relieve tectonic stresses. By applying various techniques to extensive seismic data collected by EarthScope and other permanent networks, the Principal Investigators (PIs) are creating better images of detailed fault zone structures within and below the depth where regular earthquakes occur. The PIs also hope to better understand how fault zone properties control different fault slip behaviors (regular vs slow). The project will improve our estimation of when and where large earthquakes occur and help to evaluate future seismic hazards. Because slow deformation may occur before large earthquakes, better tracking slow earthquakes could also help to better understand the processes relevant to how earthquakes initiate and interact. The PIs are developing new tutorials on triggering and detection of regular and slow earthquakes from seismic data. In addition, they are developing products to visualize and hear seismic data relevant this project. All these activities help to attract next generation scientists into the seismological field, and train them with state-of-the-art tools so that they can succeed in their future careers. This project also supports training of two graduate students and an international collaboration with Japanese researchers.Technical The newly discovered deep tectonic tremor and accompanying slow-slip events have changed our view on how accumulated tectonic stresses are released through fault movement below the seismogenic zone. Deep tremor has been clearly observed along the Parkfield-Cholame section of the San Andreas Fault (SAF) in Central California since around the time when the Earthscope project started more than 15 years ago. However, except a few cases, tremor has not been ubiquitously found along the San Jacinto Fault (SJF) and other major faults in Southern California. Although progress has been made to further understand the physical mechanisms for tremor and regular earthquakes, many fundamental questions remain open. These include: 1. What are the primary factors that control different tremor and microearthquake behaviors in Central and Southern California? 2. How do tremor and low-frequency earthquakes (LFEs) differ from regular earthquakes? 3. What are in situ fault zone properties at depth where regular and slow earthquakes occur? To answer these questions, the PIs are conducting a systematic analysis of regular and slow earthquakes in Central and Southern California using state-of-the-art techniques and available dataset in these regions. Specifically, the PIs are performing the following research tasks: 1. Detect and relocate microearthquakes along the Parkfield section of the SAF and along the SJF in Southern California; 2. Better detect and locate tremor and LFEs along the SJF in Southern California and compare their behaviors with those in Central California; 3. Quantify the triggerability of microearthquakes and tremor/LFEs in these regions; and 4. Delineate internal fault zone structures using Vp/Vs ratios and other imaging methods.The project goal is to obtain highly accurate locations of microearthquakes and LFEs in both regions, and use them to study their responses to external stress perturbations, and obtain in situ fault zone properties that control different behaviors of regular and slow earthquakes in Central and Southern California. In addition, the PIs are continuing their development of online tutorials on earthquake triggering and detection, and visualization and sonification products related to Earthscope. These activities help to educate general audience with frontier earthquake science, attract next generation scientists into the seismological field, and train them with state-of-the-art tools so that they can succeed in their future careers. This project also supports training of two graduate students and an international collaboration with Japanese researchers.

非技术性本项目旨在了解加州中部和南部的常规地震和慢震的不同行为。最近慢震的发现拓宽了我们对活动断层如何减轻构造应力的认识。通过将各种技术应用于EarthScope和其他永久网络收集的大量地震数据，首席调查员（PI）正在创建更好的详细断层带结构图像，这些断层带结构位于定期发生地震的深度之内和之下。PI还希望更好地了解断层带属性如何控制不同的断层滑动行为（常规与慢速）。该项目将改善我们对大地震发生时间和地点的估计，并有助于评估未来的地震危险。由于大地震之前可能会发生缓慢变形，因此更好地跟踪慢地震也有助于更好地了解与地震如何启动和相互作用有关的过程。PI正在开发关于从地震数据中触发和检测常规地震和慢地震的新教程。此外，他们正在开发产品，以可视化和听到与该项目相关的地震数据。所有这些活动有助于吸引下一代科学家进入地震学领域，并用最先进的工具培训他们，使他们能够在未来的职业生涯中取得成功。该项目还支持培养2名研究生，并与日本研究人员开展国际合作。技术新发现的深部构造震动和伴随的慢滑动事件改变了我们对孕震区下方断层运动释放累积构造应力的看法。自15年前“地球镜”项目开始以来，加州中部圣安德烈亚斯断层（SAF）的帕克菲尔德-乔莱姆段沿着一直清晰地观测到深震动。然而，除了少数情况下，震颤并没有被发现沿着圣哈辛托断层（SJF）和其他主要断层在南加州普遍存在。虽然在进一步了解震颤和常规地震的物理机制方面取得了进展，但许多基本问题仍然悬而未决。这些措施包括：1.控制加州中部和南部不同震颤和微地震行为的主要因素是什么？2.震颤和低频地震（LFE）与常规地震有何不同？3.在发生常规地震和慢震的深度，原地断层带的性质是什么？为了回答这些问题，PI正在使用这些地区最先进的技术和可用的数据集，对加州中部和南部的定期和缓慢地震进行系统分析。具体而言，PI正在执行以下研究任务：1。沿着SAF的帕克菲尔德段和南加州沿着SJF检测和重新定位微震; 2.更好地检测和定位南加州SJF沿着的震颤和LFE，并将其行为与中加州的行为进行比较; 3.量化这些地区的微震和震颤/LFE的可预测性; 4.利用Vp/Vs比值和其他成像方法描绘内部断层带结构。该项目的目标是获得两个地区的微震和LFE的高度精确位置，并利用它们研究它们对外部应力扰动的响应，以及获得控制加州中部和南部常规地震和慢震不同行为的原地断层带特性。此外，项目负责人正在继续开发关于地震触发和检测的在线教程，以及与Earthscope有关的可视化和声音处理产品。这些活动有助于教育普通观众前沿地震科学，吸引下一代科学家进入地震学领域，并用最先进的工具培训他们，使他们能够在未来的职业生涯中取得成功。该项目还支持培训两名研究生和与日本研究人员的国际合作。